Public water system · CA1910053
ActiveHemlock Mutual Water Co.
At a glance
Hemlock Mutual Water Co. (PWSID CA1910053) is an active community water system in Los Angeles County, California. It reports serving 686 people through 208 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
686
Service connections
208
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Hemlock Mutual Water Co. compare with other water systems in Los Angeles County?
By EPA's size categories, Hemlock Mutual Water Co. is a small system (501 to 3,300 people). Los Angeles County has 275 active public water systems. Its population served is well below the county average of 36,762 people per system, and accounts for less than 0.1% of the 10,109,668 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active community water system reports serving 6,703 people, so Hemlock Mutual Water Co. is well below that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. California has 2,997 active community water systems, 40% of the state's 7,479 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 6,179 California systems (83%) list groundwater as their primary source.
Who owns and regulates Hemlock Mutual Water Co.?
EPA lists Hemlock Mutual Water Co. as privately owned. The CA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 150 of the 275 active systems in Los Angeles County (55%) are also privately owned.
Does Hemlock Mutual Water Co. have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024. The violations listed here began between July 2009 and October 2024. By type: 5 monitoring and reporting, 4 public notice, recordkeeping or other, 1 required treatment not met, 1 reporting and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Public Notice (4 of them). EPA lists 10 as resolved and 2 as unaddressed. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Unaddressed |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2024-07-01 | Public notice, recordkeeping or otherPublic Notification Violation without NPDWR Violation · code 76 | Public Noticecode 7500 | No | Resolved |
| 2024-01-01 | Public notice, recordkeeping or otherPublic Notification Violation without NPDWR Violation · code 76 | Public Noticecode 7500 | No | Resolved |
| 2023-10-01 | Public notice, recordkeeping or otherPublic Notification Violation without NPDWR Violation · code 76 | Public Noticecode 7500 | No | Resolved |
| 2023-07-01 | Public notice, recordkeeping or otherPublic Notification Violation without NPDWR Violation · code 76 | Public Noticecode 7500 | No | Resolved |
| 2012-11-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2012-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-10-01 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2010-06-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2009-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2009-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Hemlock Mutual Water Co.: frequently asked questions
Who runs Hemlock Mutual Water Co.?
Hemlock Mutual Water Co. (PWSID CA1910053) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Hemlock Mutual Water Co. serve?
Hemlock Mutual Water Co. reports serving 686 people through 208 service connections in Los Angeles County, California.
Where does Hemlock Mutual Water Co. get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Hemlock Mutual Water Co. have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Hemlock Mutual Water Co.'s water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Hemlock Mutual Water Co.'s water quality report?
As a community water system, Hemlock Mutual Water Co. must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Los Angeles County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Los Angeles-City, Dept. of Water & Power | Los Angeles | 3,875,566 | Community | Surface water |
| Long Beach Utilities Department | Los Angeles | 466,772 | Community | Purchased surface water |
| Santa Clarita Valley Water Agency | Los Angeles | 294,090 | Community | Surface water |
| Gswc - Southwest | Los Angeles | 277,740 | Community | Purchased surface water |
| San Gabriel Valley Water Co.-El Monte | Los Angeles | 248,000 | Community | Groundwater |
| Los Angeles Cwwd 40 Reg 4 & 34 Lancaster | Los Angeles | 208,129 | Community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Hemlock Mutual Water Co., PWSID CA1910053, California”, https://aquacensus.com/water-systems/california/hemlock-mutual-water-co-ca1910053 (data as of October 1, 2026).